1. Field of the Invention
The present invention relates to a method of manufacturing a curvilinear guide rail for guiding a moving body along a curve having a given curvature in a curvilinear guide device for use in a vibration isolating apparatus applied to a precision instrument, a fine art showcase or the like, and a curvilinear guide rail manufactured according to the present method.
2. Description of the Related Art
Conventionally, as an earthquake measure for real estate such as a building or a house, or as a vibration measure when conveying a precision instrument, a fine art showcase or the like, there has been used a vibration isolating apparatus which absorbs the vibrations of the ground or a floor to relieve the shaking motion thereof. As the vibration isolating apparatus, there has been known an apparatus employing a curvilinear guide device that guides a moving body in a curvilinear manner along a curvilinear guide rail (refer to, for example, Japanese Patent Unexamined Publication No. Hei 10-122238).
FIG. 4 shows a specific example of a vibration isolating apparatus 100 with a curvilinear guide device. The vibration isolating apparatus 100 includes a first curvilinear guide device 60 fixed to a floor 50, a second curvilinear guide device 70 fixed to a supported body 51 such as a precision instrument from which vibrations are to be isolated by the apparatus 100, and a universal coupling 80 that connects those two curvilinear guide devices 60 and 70 to each other. The first and second curvilinear guide devices 60 and 70 are so disposed as to meet each other at right angles.
Also, those two curvilinear guide devices 60 and 70 respectively include curvilinear guide rails 61 and 71 respectively formed in a curved manner with their respective given curvatures, and moving bodies 62 and 72 respectively movable along their associated curvilinear guide rails 61 and 71. The universal coupling 80 connects the moving bodies 62 and 72 of the first and second curvilinear guide devices 60 and 70 to each other. The two curvilinear guide devices 60 and 70 are previously formed by bending with their respective curvatures so as not to be fixed directly to the floor which provides a plane. Therefore, they are respectively fixed to the floor 50 and supported body 51 through their associated fixing bases 63 and 73 which are formed in curved shapes respectively having the same curvatures as those of the curvilinear guide rails 61 and 71. In this specification, the term xe2x80x9cbendingxe2x80x9d means xe2x80x9cbending involved with plastic deformationxe2x80x9d, that is, means that, after the rail is once formed by bending, the rail can never be naturally restored to its original shape.
FIG. 5 is a schematic view of the above-structured vibration isolating apparatus, showing a specific method for using the same. Referring to FIG. 5, reference numeral 50 designates a floor (floor surface) and 51 stands for a supported body such as a fine art showcase. Four vibration isolating apparatuses 100 of the above-mentioned type are respectively disposed at four positions between the floor 50 and supported body 51 in such a manner as to support the supported body 51. Thanks to this arrangement, if the floor 50 is caused to shake due to an earthquake or the like, the moving bodies 62 and 72 of the first and second curvilinear guide devices 60 and 70 move on their respective curvilinear guide rails 61 and 71 in such a manner as to absorb such shaking motion of the floor 50, thereby preventing the vibrations of the floor 50 from being propagated to the supported body 51.
However, the above-mentioned conventional curvilinear guide device suffers from the following problem. That is, a guide rail, which has been formed by drawing in such a manner as to have a given sectional shape and still remains in a linear shape, is subjected to bending, thereby producing a curvilinear guide rail. Further, in this bending operation, it is necessary to bend the guide rail with a given curvature. As a result, it takes time and labor to produce the curvilinear guide rail.
Also, when forming a ball rolling surface on a curvilinear guide rail, because the ball rolling surface cannot be formed by grinding on the curvilinear guide rail after the curvilinear guide rail has been bent, such grinding operation is executed prior to the bending operation. In addition, since the hardness of the ball rolling surface must be enhanced, it is necessary to carry out heat treatment such as cementation hardening the surface of the guide rail before the grinding operation. However, when stainless steel is used as the forming material of the guide rail in order to meet the requirements such as anticorrosion, the hardening treatment hardens not only the surface of the guide rail but also the center portion thereof. As a result, if the guide rail is bent beyond the elastically deformable limit thereof, then there arises such a problem that there occurs a crack in the curvilinear guide rail produced by such bending.
The present invention has been made to eliminate the drawbacks with the above-conventional curvilinear guide rail, and therefore an object of the invention is to provide a method of manufacturing a curvilinear guide rail which, when manufacturing a curvilinear guide rail of a curvilinear guide device for guiding a moving body along a curved line having a given curvature, can manufacture the curvilinear guide rail without taking time and labor and at a low cost.
Also, another object of the invention is to provide a curvilinear guide rail which can be manufactured without taking time and labor and at a low cost.
To achieve the above objects, according to one aspect of the invention, there is provided a method for manufacturing a curvilinear guide rail for guiding a moving body along a curved line having a given curvature, the method comprising the steps of: preparing a linear guide rail for guiding a moving body in a linear manner; pressing a bottom surface of said linear guide rail against a curved rail mounting surface of a fixing base formed with a given radius of curvature to elastically deform the linear guide rail in a curvilinear manner; and fixing the linear guide rail to the rail mounting surface while the linear guide rail remains deformed elastically, to produce a curvilinear guide rail.
According to another aspect of the invention, there is provided a curvilinear guide rail for guiding a moving body along a curved line having a given curvature, the curvilinear guide rail comprising: a rail fixing base having a curved rail mounting surface formed with a given radius of curvature; a rail main body formed in a linear shape and elastically deformable in a curvilinear manner when it is pressed against the rail mounting surface of the rail fixing base; and rail fixing means for fixing the rail main body to the rail mounting surface.
In the the invention, the bottom surface of the linear guide rail is pressed against the rail mounting surface formed in a curved shape, and the linear guide rail is fixed to the rail mounting surface while the linear guide rail remains deformed within its elastically deformable range, thereby manufacturing a curvilinear guide rail for moving a moving body along a curved line having a given curvature. Thanks to this, not only a bending operation taking time and labor can be omitted, but also a curvilinear guide rail can be manufactured easily using a currently existing linear guide rail which can be obtained easily on the market, which makes it possible to manufacture a curvilinear guide rail having a given curvature at low costs.
Also, in the present invention, it is necessary to provide a rail fixing base against which the bottom surface of a linear guide rail is pressed. Similarly, even in the conventional curvilinear guide rail, when it is fixed to a floor or the like, it is necessary to use a rail fixing base having a curved rail mounting surface. However, according to the invention, the number of parts necessary for fixation of the rail is not increased over that in the conventional guide rail, but a curvilinear guide rail can be manufactured at the costs which are lowered by an amount equivalent to the elimination of the bending operation.
Further, in the invention, since the linear guide rail pressed against the bottom surface of the rail mounting surface is simply deformed within its elastically deformable range, even if it is fixed to the rail mounting surface in the deformed state, there is no fear that there can occur any crack in the linear guide rail thus fixed, and therefore, even when a curvilinear guide rail is manufactured using such material that can be cracked by a bending operation involved with plastic deformation, the present manufacturing method is surely able to cope with this problem, that is, eliminate the fear of any crack occurring in the guide rail.
Therefore, the present invention is effective in the manufacture of a curvilinear guide by using such material that is difficult to bend after it is hardened.
Also, as the rail fixing means for fixing a linear guide rail, which has been pressed against the curved rail mounting surface and elastically deformed in a curved manner, to the rail mounting surface while the linear guide rail remains elastically deformed, there can be used. any fixing means, provided that it is able to hold the linear guide rail on the rail mounting surface against the elastic force of the linear guide rail that is going to restore the linear guide rail back to its original shape. For example, a fixing bolt may be inserted through the linear guide rail and threadedly engaged with the rail mounting surface.